The packaging industry utilizes plastic and metal containers for packaging of food and beverage products, pharmaceuticals, nutritional supplements, medical devices, supplies, containment vessels, household products, auto lubricants, and other products. These plastic and metal containers can have weak properties that limit their use and usable lifecycle.
For example, the shelf life of a product may depend on several properties including: oxygen, carbon dioxide, and water vapor transmission rates through the packaging container as well as chemical reactivity between the packaging and its contents. Glass (“SiOx”) is considered the benchmark material for providing content integrity. However, producing glass containers is costly, uses large energy resources, requires sterilization, and is cumbersome in handling and shipping due to the fragile nature and weight of glass. Recently, solutions have been introduced that use plasma energy to deposit a very thin SiOx film on the interior of plastic containers to obtain the barrier properties that address weaknesses in conventional plastic containers.
Other barrier films have also been developed such as diamond-like carbon and silicon oxynitride which can also improve performance. These solutions have gained some market acceptance; however, the cost of the capital equipment, size and complexity of the machines, lack of versatility, and overall cost of ownership to run the machines provide significant barriers to entry to most packaging companies and end-users of the containers.
Existing plasma deposition systems utilize one electrode in the container and one outside. This however limits the range of container geometries that can be treated by the apparatus and adapting the apparatus is expensive and difficult because the electrode configuration depends on the geometry of the container being treated.
Additionally, systems and processes exist to treat container surfaces for other reasons, such as, sterilization, surface texturizing, creating hydrophobic or hydrophilic properties, screen printing adhesion of inks, and others. Such treatments are required in many of the industries and applications noted above.
Further, metal containers such as tin, steel, and aluminum require coatings that may contain volatile solvents that are bad for the environment and/or BPA (bisphenol A) which has been shown by the FDA (food and drug administration) to interfere with natural hormone production and balance resulting in a FDA report in 2010 highlighting concerns of BPA exposure in fetuses, infants, and young children. The method and apparatus disclosed in this specification can also treat metal containers to provide solutions that replace the coatings currently in use.
For at least these reasons, there is a need to develop equipment and processes to overcome the challenges of the existing solutions while providing for the application of barrier films or other treatments on the interior of containers.